Curing of tobacco by the "bulk curing" method involves placing a relatively compact mass of tobacco leaves within an enclosed curing barn and circulating heated air through the mass of tobacco to bring about curing and drying of the leaves. The curing cycle extends over several days, during which the tobacco is initially subjected to a controlled elevated temperature and relatively high humidity conditions to bring about a chemical change in the leaves resulting in yellowing of the leaf. Following yellowing, the temperature is increased and the humidity reduced to bring about setting of the color and drying of the leaves and stems.
When drying is completed, it is generally necessary to restore some of the moisture which was removed during the drying operation. This procedure, conventionally referred to as "ordering", is necessary in order to restore flexibility to the leaves to permit handling of the tobacco without crumbling. In the conventional barn curing procedures which have been practiced for many years, ordering was often accomplished by simply opening the doors to the barn and allowing the relatively humid outside air to contact the tobacco. Sometimes, the ordering was speeded up somewhat by wetting down the floor of the barn prior to removal of the tobacco from the barn.
These prior procedures for ordering tobacco have also been followed to some extent with bulk curing. However, as applied to bulk curing, these procedures are relatively slow and undesirably limit the utilization of the bulk curing barn. Additionally, these procedures provide no effective control over the amount of moisture restored to the tobacco. Ordering serves not only to restore flexibility to the leaves but serves also to restore weight. Since the tobacco is sold by weight, it is important in order to obtain the maximum price for the tobacco that the moisture content be within certain desired limits. Tobacco having a moisture content less than the optimum level will weigh less and will consequently bring a lower total price, while tobacco having a moisture content in excess of the desired limits is regarded as being of lower grade and will generally be sold at a reduced price per pound.
With the foregoing in mind, it is an important object of this invention to provide a practical and effective apparatus and method which is suitable for use with a tobacco bulk curing barn for ordering the tobacco.
It is another object of this invention to provide an apparatus and method for ordering tobacco in a bulk curing barn which permits increasing the humidity conditions within the curing chamber in a controlled manner as needed to bring about the desired moisture content in the tobacco.
It is another object of this invention to provide an apparatus and method of the type described which is useful not only for restoring a desired moisture content to the tobacco during ordering, but which may also be used for providing more effective control over the humidity conditions in the curing chamber during other portions of the curing cycle, such as during yellowing for example.
It is still another object of this invention to provide an apparatus and method of the type described which may be readily used in conjunction with a variety of different types of existing bulk curing barns, without requiring substantial modification thereto.
In accordance with this invention these and other objects are achieved by means of a relatively simple and reliable device which may be easily secured to a bulk curing barn and which is operable for increasing the moisture content of the tobacco in the curing chamber in a controlled manner. The apparatus of the present invention comprises an air permeable pad positioned in the flow path of the outside air which enters the housing of the tobacco curing barn and means associated therewith for distributing water onto the air permeable pad and into contact with the air passing therethrough so as to humidify the air upon entering the curing barn.
More particularly, the air permeable pad is mounted in a vertical orientation for the flow of air generally horizontally therethrough and means is provided for directing water onto the uppermost edge portion of the pad so that the water may flow by gravity downwardly through the pad and into contact with the air passing therethrough. The pad is mounted in a generally rectangular frame which surroundingly engages the perimeter of the pad and serves for mounting the ordering device in the proper position across the fresh air inlet of the curing barn.
The method of ordering bulk cured tobacco in accordance with this invention comprises the steps of drawing air from outside the curing barn into the barn and into and through a porous pad wetted with water to humidify the air upon entering the curing barn, and directing the thus humidified air into and through the curing chamber of the barn and into contact with the cured and dried tobacco positioned therein to thereby restore moisture to the tobacco and facilitate subsequent handling thereof.
The ordering device of this invention is also useful for preventing premature color setting of the tobacco during yellowing. This aspect of the present invention involves drawing air from outside the curing barn into the barn and into and through a porous pad wetted with water to humidify the air upon entering the curing barn, and then directing the thus humidified air into and through the curing chamber of the curing barn and into contact with the tobacco which is undergoing yellowing to prevent excessive drying and premature color setting of the tobacco during yellowing.